<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>talk</title>
<style type="text/css">
div {
	position: relative;
	width: 500px;
	height: 300px;
	border: 1px solid black;
	border-radius: 50%;
	font-size: 24px;
	font-weight: bold;
	text-align: center;
	line-height: 300px;
}
div:before,
div:after {
	position: absolute;
	content: "";
	display: block;
	border: 1px solid black;
	border-radius: 50%;
}
div:before {
	width: 50px;
	height: 50px;
	bottom: -25px;
	right: 25px;
}
div:after {
	width: 20px;
	height: 20px;
	bottom: -50px;
	right: 0;
}
</style>
</head>
<body>
	<div>大家好，欢迎来到尚硅谷！</div>
</body>
</html>